U.S. patent application number 10/432359 was filed with the patent office on 2004-02-12 for solenoid valve.
Invention is credited to Hayakawa, Hideyuki, Hosoi, Noriyuki, Majima, Yozo, Yabuki, Yuji.
Application Number | 20040026643 10/432359 |
Document ID | / |
Family ID | 19078423 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040026643 |
Kind Code |
A1 |
Hayakawa, Hideyuki ; et
al. |
February 12, 2004 |
Solenoid valve
Abstract
According to the present invention, a cylindrical member of a
solenoid valve is provided with a protruding portion that protrudes
in an axial direction of the cylindrical member. By fitting the
protruding portion into a vertical groove of a plunger, it is
possible to restrict the cylindrical member from moving in a
peripheral direction of the plunger. Therefore, it is possible to
prevent change of the flow path that passes the plunger and the
vertical groove, as well as to prevent variation in a sliding speed
of the plunger or the like. As a result, a fluid pulsation
reduction effect is obtained.
Inventors: |
Hayakawa, Hideyuki;
(Nishio-city, JP) ; Majima, Yozo; (Kariya-city,
JP) ; Yabuki, Yuji; (Kariya-city, JP) ; Hosoi,
Noriyuki; (Kariya-city, JP) |
Correspondence
Address: |
POSZ & BETHARDS, PLC
11250 ROGER BACON DRIVE
SUITE 10
RESTON
VA
20190
US
|
Family ID: |
19078423 |
Appl. No.: |
10/432359 |
Filed: |
May 30, 2003 |
PCT Filed: |
August 8, 2002 |
PCT NO: |
PCT/JP02/08150 |
Current U.S.
Class: |
251/129.15 |
Current CPC
Class: |
F16K 31/0665 20130101;
H01F 7/081 20130101; H01F 17/062 20130101; F16K 31/0624 20130101;
F16K 31/0689 20130101; B60T 8/363 20130101; H01F 7/1607
20130101 |
Class at
Publication: |
251/129.15 |
International
Class: |
F16K 031/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 20, 2001 |
JP |
2001-249420 |
Claims
What is claimed is:
1. A solenoid valve comprising: a sleeve formed in a cup-like shape
having a cylindrical portion and a bottom face, with one end side
of the sleeve being an opening portion; a coil provided on an outer
periphery of the sleeve; a plunger that is housed in the sleeve and
for performing a sliding movement in the sleeve by applying current
to the coil, wherein the plunger includes a vertical groove formed
on an outer peripheral surface thereof along a sliding direction
and a groove portion that is formed on an outer peripheral surface
of the plunger around an outer periphery thereof; a valve body
which moves in accordance with the sliding movement of the plunger;
a seat valve having a valve seat which the valve body seats on and
separates from, and a communication path that is opened and closed
when the valve seat seats on and separates from the valve seat; a
cylindrical member provided with a communication path having an
orifice that enables fluid to move in a sliding direction of the
plunger is fitted into the groove portion; and a positioning
portion restricting movement of the cylindrical member in a
peripheral direction of the plunger is provided in at least one of
the plunger and the cylindrical member, wherein the cylindrical
member is assembled to the plunger such that the positioning
portion aligns the vertical groove with the communication path
having the orifice.
2. The solenoid valve according to claim 1, wherein the cylindrical
member includes a protruding portion that protrudes in an axial
direction of the cylindrical member acting as the positioning
portion at a portion where the orifice is formed and is fitted into
the vertical groove.
3. The solenoid valve according to claim 1, wherein the cylindrical
member includes a protruding portion that protrudes in a radial
direction of the cylindrical member acting as the positioning
portion on an inner peripheral surface thereof, and the plunger has
a concave portion provided in the groove portion, into which the
protruding portion is fitted.
4. The solenoid valve according to claim 1, wherein the cylindrical
member includes a bias cut portion formed by a cut-through portion
for cutting itself, and wherein the bias cut portion is formed in a
shape that inclines toward with respect to the axial direction of
the cylindrical member.
5. The solenoid valve according to claim 1, wherein the cylindrical
member includes a bias cut portion formed by a cut-through portion
for cutting itself, and wherein the bias cut portion is formed in a
stepped shape having a portion that is parallel with a peripheral
direction of the cylindrical member.
6. The solenoid valve according to claim 1, wherein the groove
portion of the plunger includes a side wall face that is not
chamfered.
7. A solenoid valve comprising: a sleeve formed in a cup-like shape
having a cylindrical portion and a bottom face, with one end side
of the sleeve being an opening portion; a coil provided on an outer
periphery of the sleeve; a plunger that is housed in the sleeve and
for performing a sliding movement in the sleeve by applying current
to the coil, wherein the plunger includes a vertical groove formed
on an outer peripheral surface thereof along a sliding direction
and a groove portion that is formed on an outer peripheral surface
of the plunger around an outer periphery thereof, a valve body
which moves in accordance with the sliding movement of the plunger;
a seat valve having a valve seat which the valve body seats on and
separates from, and a communication path that is opened and closed
when the valve seat seats on and separates from the valve seat; and
a cylindrical member provided with a communication path having an
orifice that enables fluid to move in a sliding direction of the
plunger is fitted into the groove portion, and wherein the
cylindrical member includes a bias cut portion formed by a
cut-through portion for cutting itself, and wherein the bias cut
portion is formed in a stepped shape having a portion that is
parallel with a peripheral direction of the cylindrical member.
8. The solenoid valve according to claim 1, wherein the orifice and
a portion having a larger flow path area than the orifice are
disposed in series along a flow direction of the fluid in the
communication path having the orifice.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of
Japanese Patent Application No. 2001-249420 filed on Aug. 20, 2001,
and PCT Application No. PCT/JP02/08150 filed on Aug. 8, 2002 the
content of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a solenoid valve for which
opening and closing of a flow path is controlled by applying
current to a coil. The present invention is preferably applied, for
example, to a brake fluid pressure control valve disposed in a
conduit of an ABS actuator provided in a vehicular braking
apparatus.
RELATED ART OF THE INVENTION
[0003] FIG. 10 is across sectional view of a conventional solenoid
valve J1. In the solenoid valve J1, when current is not applied to
a coil J2, a plunger J4 is urged by elastic force of a spring J3,
and a ball J6 provided at a tip of a shaft J5 that moves together
with the plunger J4 separates from a valve seat J8 of a seat valve
J7. Thus, a conduit A is in an opened state. When current is
applied to the coil J2, the plunger J4 is urged in resistance to
the elastic force of the spring J3, and the ball J6 provided at the
tip of the shaft J5 is seated on the valve seat J8 of the seat
valve J7. Accordingly, the conduit A is in a closed state. Further,
a vertical groove J9 that is parallel with a sliding direction of
the plunger J4 is formed on the outer periphery of the plunger J4.
Movement of fluid through the vertical groove J9 facilitates
sliding of the plunger J4.
[0004] In the type of solenoid valve J1, when the conduit A is
opened and closed quickly, fluid pulsation becomes more substantial
and thus problems such as an abnormal noise occur. Accordingly, a
groove portion J10 is provided on an outer periphery of the plunger
J4, and a ring shaped member J11 made of a resin is disposed in the
groove portion J10. An orifice (fluid throttle) J12 that
communicates with the vertical groove J9 is provided in the groove
portion J10, and thus, a sliding speed of the plunger J4 becomes
slower and a fluid pulsation reduction effect is obtained.
[0005] In the above mentioned configuration, since the ring shaped
member J11 is assembled arbitrarily, there are cases in which
relative displacement of the orifice J12 and the vertical groove J9
is generated, making it difficult to ensure a flow path. Therefore,
in order to ensure the flow path, a chamfered portion J13 is
provided such that a side wall face of the groove portion J10 is
tapered, and the fluid is allowed to pass through the chamfered
portion J13.
[0006] In the aforementioned conventional solenoid valve J1,
relative displacement of the orifice J12 and the vertical groove J9
is generated by arbitrary assembly of the ring shaped member J1.
The relative displacement, as shown in FIGS. 11A and 11B, changes
the flow path (as shown by arrows in the drawing) of the fluid that
passes the orifice J12 and the vertical groove J9, causing
variation in flow path resistance. In such a case, variation in the
sliding speed, or the like, of the plunger J4 occurs, and thus it
is no longer possible to obtain sufficient fluid pulsation
reduction effect.
[0007] Moreover, if the flow path is ensured by providing the
chamfered portion J13 on the groove portion J10, a cross sectional
area D of a portion of the plunger J4 at which the chamfered
portion J13 is provided becomes smaller. Accordingly, attraction
force is reduced.
[0008] Further, assembly of the ring shaped member J11 to the
plunger J4 is executed by press-expanding the ring shaped member
J11 using a bias cut portion (a cut-through portion) , not shown,
which is formed in the ring shaped member J11. However, fluid leaks
through the bias cut portion, and thus the sliding speed of the
plunger J4 deviates from a required set value.
DISCLOSURE OF THE INVENTION
[0009] It is therefore an object of the present invention to
provide a solenoid valve that is capable of obviating the above
problems.
[0010] It is an object of the present invention to eliminate
variation in the flow path resistance caused by arbitrary assembly
of a ring shaped member having an orifice, and to ensure sufficient
fluid pulsation reduction effect.
[0011] It is further object of the present invention to ensure a
cross sectional area of a plunger to prevent decrease in attraction
force.
[0012] Moreover, it is object of the present invention to prevent
fluid leakage through a bias cut portion.
[0013] According to the present invention, a solenoid valve
includes a vertical groove formed along a sliding direction of a
plunger, a groove portion that is formed around an outer periphery
of the plunger are provided on an outer peripheral surface of the
plunger, a cylindrical member provided with a communication path
having an orifice that allows fluid to move in a sliding direction
of the plunger is fitted into the groove portion, a positioning
portion restricting movement of the cylindrical member in a
peripheral direction of the plunger is provided in at least one of
the plunger and the cylindrical member, and the cylindrical member
is assembled to the plunger such that the positioning portion
aligns the vertical groove with the communication path having the
orifice.
[0014] Accordingly, the positioning portion is able to align the
vertical groove with the communication path formed by the orifice.
Therefore, it is possible to prevent change of flow path that
passes the orifice and the vertical groove of the plunger, and
variation in a sliding speed of the plunger. As a result, it is
possible to obtain sufficient fluid pulsation reduction effect.
[0015] A solenoid valve according to the present invention may be
provided with, for example, a protruding portion that protrudes in
an axial direction of the cylindrical member at a portion of the
cylindrical member where the orifice is formed. This protruding
portion serves as the positioning portion. By fitting the
protruding portion into the vertical groove, it is possible to
align the vertical groove with the communication path having the
orifice.
[0016] Alternatively, a solenoid valve according to the present
invention may be provided with a protruding portion that protrudes
in a radial direction of the cylindrical member at an inner
peripheral surface of the cylindrical member. The protruding
portion serves as the positioning portion. A concave portion into
which the protruding portion is fitted is provided in the groove
portion. By fitting the protruding portion into the concave
portion, it is possible to align the vertical groove and the
communication path having the orifice.
[0017] A solenoid valve according to the present invention may be
characterized in that a bias cut portion formed by a cut-through
portion that divides the cylindrical member is formed in the
cylindrical member. This bias cut portion is formed in a shape that
inclines toward with respect to the axial direction of the
cylindrical member. Such a construction allows the bias cut portion
to be lengthened, and thus a flow resistance of the fluid becomes
larger at the bias cut portion. Therefore, it is possible to
inhibit fluid leakage through the bias cut portion.
[0018] A solenoid valve according to the present invention may be
characterized in that a bias cut portion formed by a cut-through
portion that divides the cylindrical member is formed in the
cylindrical member. The bias cut portion is formed in a stepped
shape having a portion that is parallel with a peripheral direction
of the cylindrical member. In such a construction, even if the
cylindrical member expands in the radial direction, the portion
parallel with the peripheral direction of the cylindrical member of
the bias cut portion shuts off the flow path at the bias cut
portion. Accordingly, it is possible to prevent fluid leakage
through the bias cut portion.
[0019] A solenoid valve according to the present invention may be
characterized in that a side wall face of the groove portion of the
plunger is not chamfered. In this case, however, some cases where
chamfering of approx. 0.1 to 0.2 mm is allowed to remove burrs, or
the like. Accordingly, it is possible to ensure a large cross
sectional area of the plunger and prevent decrease in attraction
force.
[0020] A solenoid valve according to the present invention may be
characterized in that the orifice and a portion having a larger
flow path area than the orifice are disposed in series along a flow
direction of the fluid in the communication path having the
orifice.
[0021] Accordingly, the orifice is shorter and dimensional accuracy
in processing is improved, thereby reducing variation in the flow
path resistance.
[0022] It should be noted that the above reference numerals in
parentheses indicate individual portions. These reference numerals
correspond with specific portions to be described in the later
embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Other objects, features and advantages of the present
invention will be understood more fully from the following detailed
description made with reference to the accompanying drawings. In
the drawings:
[0024] FIG. 1 is a cross sectional view of a solenoid valve 1
according to a first embodiment of the present invention;
[0025] FIG. 2 is an enlarged view of a vicinity portion of a
cylindrical member 12 of FIG. 1;
[0026] FIG. 3A is a top view of the cylindrical member 12;
[0027] FIG. 3B is a partial cross sectional view of the cylindrical
member 12 viewed from the front;
[0028] FIG. 3C is a partial cross sectional view of the cylindrical
member 12 viewed from the right side of FIG. 3B;
[0029] FIG. 4 is a bar graph comparing a magnetic force of the
solenoid valve 1 according to the first embodiment of the present
invention and that of a related art solenoid valve J1;
[0030] FIG. 5A is a top view of the cylindrical member 12;
[0031] FIG. 5B is a partial cross sectional view of the cylindrical
member 12 viewed from the front;
[0032] FIG. 5C is a partial cross sectional view of the cylindrical
member 12 viewed from the right side of FIG. 5B;
[0033] FIG. 6A is a top view of the cylindrical member 12;
[0034] FIG. 6B is a partial cross sectional view of the cylindrical
member 12 viewed from the front;
[0035] FIG. 6C is a partial cross sectional view of the cylindrical
member 12 viewed the right side of FIG. 6B;
[0036] FIG. 7A is a top view of the cylindrical member 12;
[0037] FIG. 7B is a partial cross sectional view of the cylindrical
member 12 viewed from the front;
[0038] FIG. 7C is a partial cross sectional view of the cylindrical
member 12 viewed from the right side of FIG. 7B;
[0039] FIG. 8 is a cross sectional view of the solenoid valve 1
according to a fifth embodiment of the present invention;
[0040] FIG. 9A is a top view of the cylindrical member 12;
[0041] FIG. 9B is a partial sectional view viewed from the
front;
[0042] FIG. 9C is a partial sectional view of the cylindrical
member 12 viewed from the right side of FIG. 9B;
[0043] FIG. 9D is a partial sectional view of the cylindrical
member 12 according to another modification of the fifth
embodiment;
[0044] FIG. 9E is a partial sectional view of the cylindrical
member 12 according to another modification of the fifth
embodiment;
[0045] FIG. 10 is a cross sectional view of the related art
solenoid valve J1; and
[0046] FIG. 11 shows a difference of flow paths when a ring shaped
member J11 is displaced.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0047] The present invention will be described further with
reference to various embodiments in the drawings.
(First Embodiment)
[0048] FIG. 1 is a cross sectional view of a solenoid valve 1
according to a first embodiment of the present invention, and FIG.
2 is a sectional view taken along line A-A of FIG. 1. The solenoid
valve 1 is, for example, disposed in a conduit A for a brake fluid
formed in a housing 2 of an ABS actuator. FIG. 1 shows a state when
normal braking is executed, that is, a state in which current is
not applied to a coil.
[0049] As shown in FIG. 1, the solenoid valve 1 is provided with a
guide 3 made of a magnetic material. The guide 3 is formed in a
stepped cylindrical shape such that a large diameter portion side
of the guide 3 is fitted into a concave portion 4 of the housing 2
of the ABS actuator. Further, a part of the housing 2 is fitted
into a recess provided in the guide 3 by deforming the vicinity of
an opening end of the concave portion 4 of the housing 2, and thus
the guide 3 is fixed to the housing 2.
[0050] The guide 3 includes a guide hole 3a that is positioned at a
small diameter side of the guide 3 and holds a shaft 5 slidably, a
seat insertion hole 3b that is positioned at a large diameter side
of the guide 3 and into which a seat valve 6 is pressed, and a
communication hole 3d for communicating a space 3c surrounded by
the seat valve 6 and the seat insertion hole 3b with the conduit A
formed in the housing 2.
[0051] The shaft 5 is formed of non-magnetic metal (such as
stainless steel). The shaft 5 is shaped so as to be cylindrical,
and an end portion thereof at the side of the seat valve 6
protrudes and extends from the guide hole 3a into the space 3c. A
ball (valve body) 5a is welded to the tip of the end portion.
[0052] The seat valve 6 is formed in a cylindrical shape. A first
communication path 6a is formed at a central portion in a radial
direction of the seat valve 6 for communicating the space 3c in the
guide 3 to the conduit A formed in the housing 2. Further, a
tapered first valve seat 6b, which the ball 5a of the shaft 5 seats
on and separates from, is formed at an end portion of the first
communication path 6a on the side of the space. Moreover, a second
communication path 6c for communicating the space 3c in the guide 3
to the conduit A is formed in parallel with the first communication
path 6a in the seat valve. A tapered second valve seat 6d which a
spherical check valve 7 seats on and separates from is formed in
the second communication path 6c, at an end portion on the opposite
side to the shaft 5.
[0053] The check valve 7 is held at a position opposite to the
second valve seat 6d by a filter 8 pressed into a side of an end
portion of the seat insertion hole 3b of the guide 3. A filter 9 is
also disposed on an outer periphery of the large diameter portion
of the guide 3 so as to surround the communication path 3d. The
filters 8 and 9 prevent foreign matter mixed within the fluid from
entering the solenoid valve 1.
[0054] An outer peripheral side of a small diameter portion of the
guide 3 is fitted into a sleeve 10. The sleeve 10, made of
non-magnetic metal (e.g., stainless steel) , is formed in a
cup-like shape having a cylindrical portion with one end that is
open. A bottom face thereof is substantially spherical. A
substantially cylindrical plunger 11 made of a non-magnetic
material is disposed at a side of the bottom face of the sleeve 10,
and the plunger 11 is slidable in the sleeve 10. The plunger 11
contacts the bottom face of the sleeve 10. When the plunger 11
contacts with the bottom face of the sleeve 10, a sliding movement
of the plunger 11 in a direction toward the upper side of the
drawing is restricted.
[0055] A vertical groove 11a that is parallel with a sliding
direction of the plunger 11 is formed on an outer peripheral
surface of the plunger 11. Movement of the fluid through the
vertical groove 11a enables the plunger 11 to easily slide in the
sleeve 10. A groove portion 11b running around the outer periphery
of the plunger 11 is formed on an outer peripheral surface. A side
wall face of the groove portion 11b is not chamfered, or, if it is
slightly chamfered so that chamfering is only performed to a small
portion. The cylindrical member 12 is disposed in the groove
portion 11b.
[0056] FIGS. 3A-3C are a schematic views of the cylindrical member
12. FIG. 3A is a top view of the cylindrical member 12 (viewed from
a top of FIG. 1). FIG. 3B is a partial cross sectional view of the
cylindrical member 12 viewed from the front, and FIG. 3C is a
partial cross sectional view of the cylindrical member 12 viewed
from the right side of FIG. 3B.
[0057] The cylindrical member 12 has a substantially rectangular
cross-section when cut along an axial direction of the plunger 11.
The cylindrical member 12 is thin in a radial direction, and thick
in an axial direction (i.e. a sliding direction of the plunger 11).
Moreover, a longitudinal direction of the cylindrical member 12 is
along with the sliding direction of the plunger 11.
[0058] The cylindrical member 12 is made of a resin with a large
coefficient of linear expansion such as
10.times.10.sup.-5/.degree.C. or more. The cylindrical member 12 is
provided with a communication path 12a that is parallel with a
movement direction of the plunger 11, and an orifice 12b disposed
in the communication path 12a. The orifice 12b restricts an amount
of the fluid that flows through the communication path 12a.
[0059] More specifically, the orifice 12b and a portion having a
larger flow path area than the orifice 12b are disposed in series
in the communication path 12a of the cylindrical member 12.
Accordingly, the orifice 12b is made shorter and dimensional
accuracy during processing of the orifice 12b is improved, thereby
reducing variation in the flow path resistance.
[0060] The cylindrical member 12 is provided with protruding
portions 12c that protrude at both sides in the axial direction.
The protruding portions 12c are formed on both sides of the flow
path which is formed by the orifice 12b, and this pair of
protruding portions are fitted into the vertical groove 11a of the
plunger 11. The width of the pair of protruding portions 12c, on
respective sides, is the same as the width of the vertical groove
11a, and fitting of the pair of protruding portions 12c into the
vertical groove 11a defines positioning of the orifice 12b and the
vertical groove 11a. Accordingly, the vertical groove 11a is
aligned with the communication path 12a formed by the orifice
12b.
[0061] Moreover, at a high temperature the cylindrical member 12
has the same length in the sliding direction of the plunger 11 as
the groove portion 11b. At a low temperature, length of the
cylindrical member 12 is smaller than that of the groove portion
11b. Specifically, it has been confirmed that an amount of gap
created between the cylindrical member 12 and the groove portion
11b in the sliding direction of the plunger 11 is proportional to a
response time of the solenoid valve 1. Thus, the lengths of the
cylindrical member 12 and the groove portion 11b are set such that,
at the low temperature, the amount of gap created between the
cylindrical member 12 and the groove portion 11b is equal to an
amount of gap according with a required response time of the
solenoid valve 1.
[0062] Further, as shown in FIG. 3C, a bias cut portion 12d for
dividing the cylindrical member 12 is formed in the cylindrical
member 12, at a position which is different to the position at
which the orifice 12b is formed. By press-expanding the cylindrical
member 12 with the bias cut portion 12d, the cylindrical member 12
can be fitted into the groove portion 11b. The bias cut portion 12d
is formed as a cut-through portion that is inclined with respect to
the axial direction of the cylindrical member 12. It is formed so
as to be longer than in the case the bias cut portion is formed in
parallel with the sliding direction of the plunger 11.
[0063] The shaft 5 is urged to the plunger 11 side by a spring 13
disposed between the shaft 5 and the seat valve 6, and the shaft 5
always abuts against the plunger 11 so as to operate integrally.
Note that the shaft 5 and the plunger 11 configure movable members
that move based on whether or not current is applied to a coil
1.
[0064] A cylindrical spool 15 is disposed around the sleeve 10, and
houses the coil 14 that creates a magnetic field when current is
applied. The spool 15, made of a resin (such as nylon), is formed
by performing a secondary molding subsequent to attaching the coil
14 following a primary molding. A yoke 16 with a cup-like shape
made of a magnetic material is formed on the outer periphery of the
spool 15, and the yoke 16 houses the spool 15 and the coil 14. An
opening portion is formed at a central portion of the bottom face
of the yoke 16, and the bottom face side of the sleeve 10 is fitted
into the opening portion. Terminals, not shown, are retracted from
the coil 14. Current can be applied to the coil 14 through the
terminals.
[0065] At an inlet side of the yoke 16, a ring shaped positioning
member 17 is disposed between the yoke 16 and the large diameter
portion of the guide 3 for positioning the yoke 16 and the guide
3.
[0066] Next, operation of the solenoid valve 1 with the
aforementioned configuration will be described. As mentioned above,
FIG. 1 shows a state of the solenoid valve 1 when current is not
applied to the coil 14. As shown in FIG. 1, when current is not
applied to the coil 14, the shaft 5 and the plunger 11 are urged
toward the side of the bottom face of the sleeve 10 by elastic
force of the spring 13, such that the plunger 11 contacts the
bottom face of the sleeve 10. Then, the ball 5a of the shaft 5
separates from the first valve seat 6b of the seat valve 6, and the
conduit A is in a communication state (opened state) through the
first communication path 6a, the space 3c in the guide 3, and the
communication hole 3d of the guide 3. Therefore, the solenoid valve
1 is in a communication state when current is not applied to the
coil 14.
[0067] On the other hand, when current is applied to the coil 14, a
magnetic field is created by the coil 14, and a magnetic path is
formed by the guide 3, the plunger 11, the yoke 16 and the ring
member 17. Next, the plunger 11 is attracted toward the guide 3
side by magnetic attraction force, and thus the shaft 5 and the
plunger 11 are moved toward the side of the seat valve 6 resisting
the spring 13. Accordingly, the ball 5a of the shaft 5 is seated on
the first valve seat 6b of the seat valve 6 and the solenoid valve
1 is placed in a shut-off state (closed state).
[0068] During opening and closing operation of the solenoid valve
1, when the temperature is normal to high, the amount of a gap
between the cylindrical member 12 and the groove portion 11b of the
plunger 11 in the sliding direction of the plunger 11 is
substantially zero. Therefore, sliding speed of the plunger is
reduced due to a throttling effect of the orifice 12b formed in the
cylindrical member 12. Accordingly, it is possible to slow down the
opening and closing operation of the conduit A (flow path) by the
solenoid valve 1, and a fluid pulsation reduction effect is
obtained.
[0069] On the contrary, when the temperature is low, the gap is
increased between the cylindrical member 12 and the groove portion
11b of the plunger 11 in the sliding direction. Therefore, even if
viscous resistance of the fluid at a low temperature is larger than
that at a normal temperature, the plunger 11 slides easily.
Accordingly, the opening and closing operation of the conduit A by
the solenoid valve 1 is performed at a desired slow speed, that is,
the operation is not executed too slowly. As a result,
responsiveness at a low temperature can be enhanced.
[0070] When performing such the operation with the solenoid valve 1
according to the present embodiment, the protruding portions 12c
provided in the cylindrical member 12 act as a positioning portion
so as to align the vertical groove 11a with the communication path
12a formed by the orifice 12b. Accordingly, of the flow path that
passes through the orifice 12b and the vertical groove 11a of the
plunger his not changed, and it is possible to decrease variation
in a sliding speed, or the like of the plunger 11. As a result,
sufficient fluid pulsation reduction effect is obtained.
[0071] According to the present embodiment, the sidewall face of
the groove portion 11b formed in the plunger 11 is not chamfered,
or, if it is slightly chamfered so that chamfering is only
performed to a small portion. This is achieved because the orifice
12b is aligned with the vertical groove 11a as mentioned above, and
thus the fluid reliably flows through the orifice 12b even if
chamfering is hardly formed at all. This construction ensures a
large cross sectional area D of the plunger 11. FIG. 4 shows a
result of a comparison between magnetic attraction forces of the
solenoid valve 1 according to the present embodiment and that of
the related art chamfered solenoid valve J1. As is apparent from
the result, the solenoid valve 1 according to the present
embodiment satisfies a required attraction force, thereby
preventing decrease in magnetic attraction force.
[0072] Moreover, since the cylindrical member 12 is formed so as to
be wide according to the present embodiment, it is possible to
ensure that the bias cut portion 12d is long. Accordingly, flow
resistance of the fluid increases through the bias cut portion 12d
and fluid leakage through the bias cut portion 12d is therefore
inhibited. Since the groove portion 11b is not chamfered
substantially, only minimal fluid flow to the bias cut portion 12d
through the chamfered portion is possible. Therefore, fluid leakage
through the bias cut portion 12d is further inhibited.
[0073] Moreover, since the cylindrical member 12 is thin in the
radial direction, flexural rigidity of the cylindrical member 12 is
small. Therefore, when the fluid pressure, which is generated
during the plunger 11 slides, acts on the inner peripheral surface
side of the cylindrical member 12, the cylindrical member 12 is
easily deformed such that the outer peripheral surface of the
cylindrical member 12 contacts the inner peripheral surface of the
sleeve 10. Accordingly, the boundary of these two members is
reliably sealed.
[0074] If the cylindrical member 12 is made of nylon 6T,
polytetrafluoroethylene, or the like, which has low water absorbing
properties, it is possible to reduce the change in outside
dimensions to a minimum, and reduce the difference in diameter of
the cylinder member 12 from the inner diameter of the sleeve 10.
Therefore, leakage from the bias cut portion 12d is further
reduced.
(Second Embodiment)
[0075] FIGS. 5A-5C are schematic views of the cylindrical member 12
according to a second embodiment of the present invention. FIG. 5A
is atop view of the cylindrical member 12. FIG. 5B is a partial
cross sectional view of the cylindrical member 12 viewed from the
front. FIG. 5C is a partial cross sectional view of the cylindrical
member 12 viewed from the right side of FIG. 5B. The second
embodiment only differs from the first embodiment in that the
cylindrical member 12 has been modified. Since other elements of
the solenoid valve 1 are the same as in the first embodiment, only
a portion which is different will be described.
[0076] In the first embodiment, the orifice 12b is formed by the
partially narrowed communication path 12a which is formed in a
groove-like shape on the outer peripheral surface of the
cylindrical member 12. On the contrary, according to the second
embodiment, the orifice 12b is formed by partially drilling the
cylindrical member 12. According to the second embodiment in which
the orifice 12b is formed by drilling, an effect is obtained that
is similar to that of the first embodiment.
(Third Embodiment)
[0077] FIGS. 6A-6C are schematic views of the cylindrical member 12
according to a third embodiment of the present invention. FIG. 6A
is a top view of the cylindrical member 12. FIG. 6B is a partial
cross sectional view of the cylindrical member 12 viewed from the
front. FIG. 6C is a partial cross sectional view of the cylindrical
member 12 viewed from the right side of FIG. 6B. The third
embodiment only differs from the first embodiment in that the
cylindrical member 12 has been modified. Since other elements of
the solenoid valve 1 are the same as in the first embodiment, only
a portion which is different will be described.
[0078] In the first embodiment, the cylindrical member 12 and the
plunger 11 are positioned by the protruding portions 12c that
protrude at both sides in the axial direction of the cylindrical
member 12. On the contrary, according to the third embodiment, a
concave portion is formed in the groove portion 11b of the plunger
11, and the cylindrical member 12 and the plunger 11 are positioned
by fitting a protruding portion 12e protruding in the radial
direction from the inner diameter side of the cylindrical member 12
into the concave portion in the groove portion 11b.
[0079] The above configuration also aligns the communication path
12a of the cylindrical member 12 with the vertical groove 11a of
the plunger 11. Accordingly, an effect is obtained that is similar
to that of the first embodiment.
(Fourth embodiment)
[0080] FIGS. 7A-7C are schematic views of the cylindrical member 12
according to a fourth embodiment of the present invention. FIG. 7A
is a top view of the cylindrical member 12. FIG. 7B is a partial
cross sectional view of the cylindrical member 12 viewed from the
front. FIG. 7C is a partial cross sectional view of the cylindrical
member 12 viewed from the right side of FIG. 7B. Since the fourth
embodiment only differs from the first embodiment in that the
cylindrical member 12 has been modified. Since other elements of
the solenoid valve 1 are the same as in the first embodiment, only
a portion which is different will be described.
[0081] According to the first embodiment described above, the bias
cut portion 12d is inclined with respect to the axial direction of
the cylindrical member 12. On the contrary, according to the fourth
embodiment, the bias cut portion 12d is formed in a stepped shape
constituted by portions that are parallel with the axial direction
of the cylindrical member 12 and a portion parallel with a
peripheral direction of the cylindrical member 12.
[0082] Accordingly, even if the cylindrical portion 12 expands in
the radial direction, the portion of the bias cut portion 12d that
is parallel with the peripheral direction of the cylindrical member
12 can shut off the flow path at the bias cut portion 12d, thereby
preventing fluid leakage through the bias cut portion 12d.
[0083] Accordingly, as in the fourth embodiment, forming of the
bias cut portion 12d in the stepped shape constituted by a portion
parallel with the axial direction of the cylindrical member 12 and
the portions parallel with the peripheral direction of the
cylindrical member 12 enables an effect that is similar to that of
the first embodiment to be obtained. Further, preventing fluid
leakage through the bias cut portion 12d is inhibited.
[0084] In the fourth embodiment, an example has been described in
which the shape of the cylindrical member 12 according to the first
embodiment is changed. However, it is also possible to prevent
fluid leakage through the bias cut portion 12d by applying the
cylindrical member 12 according to the fourth embodiment to a
conventional solenoid valve in which a side wall face of the groove
portion 11b is chamfered.
[0085] Moreover, as shown in FIG. 7D, the bias cut portion 12d
which is formed in the cylindrical member 12 may have a wide
V-shape such that a direction of the flow path formed by the bias
cut portion 12d is changed in middle portion thereof. Since such a
configuration is easy to machine and does not easily permit fluid
to flow through, it is possible to prevent fluid leakage through
the bias cut portion 12d.
(Fifth Embodiment)
[0086] FIG. 8 is a cross sectional configuration of the solenoid
valve 1 according to a fifth embodiment of the present invention.
FIG. 9A is a top view of the cylindrical member 12 of FIG. 8. FIG.
9B is a partial cross sectional view of the cylindrical member 12
viewed from the front. FIG. 9C is a partial cross sectional view of
the cylindrical member 12 viewed from the right side of FIG. 9B.
Since the fifth embodiment only differs from the first embodiment
in that the plunger 11 and the cylindrical member 12 are modified.
Since other elements of the solenoid valve 1 are the same as in the
first embodiment, only a portion which is different will be
described.
[0087] Unlike the first embodiment in which the cylindrical member
12 is provided with the protruding portions 12c, the cylindrical
member 12 according to the fifth embodiment is not provided with
protruding portions. If protruding portions are not provided as
previously described, there are cases where relative displacement
of the orifice 12b of the cylindrical member 12 and the vertical
groove 11a of the plunger 11 occurs, and thus the flow path cannot
be ensured. To avoid this problem, a chamfered portion 11c is
provided such that the side wall face of the groove portion 11b is
tapered, and thus fluid can flow through the chamfered portion 11c,
thereby ensuring the flow path.
[0088] Moreover, according to the first embodiment, the bias cut
portion 12d is inclined with respect to the axial direction of the
cylindrical member 12. On the contrary, the bias cut portion 12d of
the fifth embodiment is formed in a stepped shape configured by
portions parallel with the axial direction of the cylindrical
member 12 and a portion parallel with the peripheral direction
thereof.
[0089] Accordingly, even if the cylindrical portion 12 expands in
the radial direction, the portion of the bias cut portion 12d that
is parallel with the peripheral direction of the cylindrical member
12 can shut off the flow path at the bias cut portion 12d, thereby
preventing fluid leakage through the bias cut portion 12d.
[0090] Meanwhile, as shown in FIG. 9D, the bias cut portion 12d
which is formed in the cylindrical member 12 may have a wide
V-shape such that a direction of the flow path formed by the bias
cut portion 12d is changed in middle portion thereof. Since such a
configuration is easy to machine, and does not easily permit fluid
to flow through, it is possible to prevent fluid leakage through
the bias cut portion 12d.
[0091] Moreover, as shown in FIG. 9E, the bias cut portion 12d may
be a stepped shape configured by portions inclines toward the axial
direction of the cylindrical member 12 and a portion parallel with
the peripheral direction of the cylindrical member 12.
[0092] Accordingly, even if the cylindrical portion 12 expands in
the radial direction, the portion of the bias cut portion 12d that
is parallel with the peripheral direction of the cylindrical member
12 can shut off the flow path at the bias cut portion 12d, thereby
preventing fluid leakage through the bias cut portion 12d.
[0093] (Modification)
[0094] As well as the orifice being positioned at the protruding
portions 12c that act as the positioning portion, the orifice may
be positioned at a position that is 180.degree. around the
cylindrical member 12 with respect to the positioning portion.
Alternatively, if the plunger 11 is chamfered, the orifice may be
positioned at other positions, since a rate of fluid flow that
passes along the flow path including the chamfered portion is kept
to constant.
[0095] While the above description is of the preferred embodiments
of the present invention, it should be appreciated that the
invention may be modified, altered, or varied without deviating
from the scope and fair meaning of the following claims.
* * * * *